System and method for the spectroscopic determination of the components and concentrations of pumpable organic compounds

ABSTRACT

The present invention is directed to a fast, nondestructive measurement method for determining the contents of solid, liquid and/or suspended flowing organic compounds. The arrangement according to the invention comprises a sample vessel, a pump, and a measurement cell which form a unit together with a spectroscopic measurement head. The measurement cell is connected to the pump, which can be regulated to vary the flow rate, and to the sample vessel by a pipe, and the spectroscopic measurement head and the regulatable pump have electrical connections to a controlling and evaluating unit. Due to its compact construction, the solution which makes use of the principle of transflection is also particularly suited to mobile use, for example, to determine the components of liquid manure while the latter is being dispensed. In principle, the solution can be transferred to any applications with suspensions or pumpable, homogeneous and inhomogeneous materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of International Application No.PCT/EP2005/001799, filed Feb. 22, 2005 and German Application No. 102004 010 217.1, filed Feb. 27, 2004, the complete disclosures of whichare hereby incorporated by reference.

BACKGROUND OF THE INVENTION

a) Field of the Invention

The present invention is directed to a fast, nondestructive measurementmethod for determining the substances contained in solid, liquid and/orsuspended flowing organic compounds. The proposed solution is suitablefor calibration to a large number of relevant parameters and can be usedin all fields, particularly also in a mobile manner.

b) Description of the Related Art

The through-flow measurement cuvette described in DE 100 16 023 C2 issuitable for the combined use of spectroscopy and polarimetry for thesimultaneous determination of a plurality of measured quantities inphysical-chemical and bio-technical processes. In particular, substancesdissolved in flowing media can be detected continuously and without adelay in time and can be quantitatively determined. Wavelengths in theUV region to the NIR region can be used for spectroscopic measurement.The measurement path is located between two rods of glass, or the like,projecting into the measurement cuvette transverse to the flowdirection. Depending on the substance to be investigated, themeasurement path must be varied by displacing the rods becausemeasurements can only be carried out by transmission. However, thismakes it more difficult or impossible to use the through-flowmeasurement cuvettes for automated, mobile use.

The determination of the contents of liquid manure, for example, with aview to the precise use thereof as organic fertilizer, is particularlyimportant. Heretofore, the applicable guidelines in this case withregard to the maximum amount to be dispensed could be adhered to onlywith difficulty because an exact determination of the components andconcentrations at the moment of dispensing was impossible. It was onlypossible to monitor adherence to guidelines through soil analyses beforeor after dispensing.

According to the known prior art, the determination of the containedsubstances is carried out after taking samples by subsequent wetchemical measurements in the laboratory. This method is time-consumingand requires extensive preparation of samples. The quantity of samplesis limited, and the analysis data can be used for controlling and/orregulating processes in a timely manner only to a limited extent if atall. When the measurement is carried out in through-flow cells withconventional sensors, only the contents that are measurable selectivelyby the respective sensors can be detected.

A project (“Analysis of Nutrients in Hog Manure by Field-portableNear-infrared Spectroscopy”, July 2001) conducted by PDK Projects, Inc.,documents the use of NIR spectroscopy for determining components andconcentrations of organic waste. However, the results of this projectrelate only to the use of spectroscopic measuring instruments underlaboratory use. The samples to be determined were placed on thespectroscopic measurement head for this purpose. A compact solution fora possible mobile use on a vehicle for dispensing liquid manure was notthe aim of the project.

OBJECT AND SUMMARY OF THE INVENTION

It is the primary object of the present invention to develop a fast,nondestructive measurement method and a corresponding arrangement fordetermining the components of solid, liquid and/or suspended organicwaste. The solution is suitable for mobile use, and a high, continuousmeasurement data density can be realized.

According to the invention, this object is met in an arrangement for thespectroscopic determination of the components and concentrations ofpumpable organic waste, comprising a sample vessel, a pump and ameasurement cell which form a unit together with a spectroscopicmeasurement head. The measurement cell is connected to the pump, whichcan be regulated to vary the flow rate, and to the sample vessel by apipe. The spectroscopic measurement head and the regulatable pump haveelectrical connections to a controlling and evaluating unit.

The proposed technical solution delivers representative measurementvalues of the components of inhomogeneous material using thethrough-flow method, wherein direct measurement is carried out by lightabsorption or light transmission. Using the principle of transflection,it is possible to carry out measurements on highly absorbent samples aswell as transmissive samples, i.e., also turbid suspensions, and todetect liquid components as well as solid components of the sample.

Due to the compact construction, the solution is also particularlysuitable for mobile use for determining the components of solid, liquidand/or suspended organic compounds.

For example, the solution can be used to determine the components ofliquid manure and organic fertilizers. By determining the components ofthe fertilizer in situ, particularly also while it is being dispensed,the fertilizer can be metered in a purposeful manner depending on thedirectly determined components.

In principle, the proposed technical solution can be transferred to anyapplications with suspensions or pumpable, homogeneous and inhomogeneousmaterials. In particular, the invention can conceivably be applied inthe foodstuffs industry, sewage control, and process monitoring, e.g.,in meat processing and in the production of biogas.

The invention will be described more fully in the following withreference to an embodiment example.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a schematic diagram of the arrangement according to theinvention for use in the laboratory; and

FIG. 2 shows an arrangement which is adapted for mobile use in avehicle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the arrangement according to the invention forspectroscopic determination of the components and concentrations ofpumpable organic compounds. The arrangement comprises a sample vessel 1,a pump 2, and a measurement cell 3 which, together with a spectroscopicmeasurement head 4, form a unit. The measurement cell 3 is connected tothe pump 2, which can be regulated to vary the flow rate, and to thesample vessel 1 by a pipe 5. The spectroscopic measurement head 4 andthe regulatable pump 2 have electrical connections to a controlling andevaluating unit (not shown).

The measurement cell 3 is preferably constructed in such a way that thesample flows between two windows which are integrated in the measurementcell opposite one another and perpendicular to the direction of flow. Asthe sample flows through the measurement cell 3, it must be ensured thatno sedimentation, foaming or clogging occurs. The optimal flow ratevaries depending on the type of sample as a function of solids content,particle size, particle structure, and thixotropy.

In order to clean the measurement cell 3 of residues from the measuredsample and prepare it for the next sample, a multi-port valve 6 isprovided which produces connections to a water vessel and/or a vesselwith cleaning liquid. The multi-port valve 6 has an actuating drivewhich is connected to the controlling and evaluating unit. By means ofthis multi-port valve 6, the measurement cell can be additionallyconnected to vessels containing test liquids for self-calibration of themeasurement arrangement.

The cleaning liquid and rinsing water can be expelled via the multi-portvalve 6 after rinsing the measurement cell 3. A repeated rinsing of themeasurement cell 3 is advantageous.

The degree of contamination and any cleaning of the measurement cell 3that may be necessary can be determined by a spectroscopic measurementof the measurement cell 3 without the sample.

Further, the arrangement can have a device for drying the measurementcell 3, which device is likewise connected to the controlling andevaluating unit. Drying is carried out, for example, by aeration in thatair is pressed through the measurement cell 3 by means of a valve 7. Theair can also be expelled via the multi-port valve 6 after flowingthrough the measurement cell 3.

Since it must be assumed that the measurement results are affected bytemperature, a device for maintaining the temperature of the sample isprovided, preferably in or in front of the measurement cell 3.

In an advantageous development, the arrangement is mounted on a vehicleparticularly for dispensing pumpable organic waste.

FIG. 2 shows an arrangement which is adapted for this purpose for mobileuse on a vehicle. To this end, two additional three-way directionalvalves 8 and 9 are arranged in the pipe 5. In order to determine thecomponents and concentrations while dispensing, a sample is taken fromthe outlet line of the tank by means of the three-way directional valve8, pumped through the measurement cell 3, and guided back into theoutlet line of the tank by the three-way directional valves 9. Thethree-way directional valves 8 and 9 preferably likewise have actuatingdrives which are connected to the controlling and evaluating unit. Thesample vessel 1 can remain in the arrangement during this period so thata closed circuit is provided for the rinsing and/or drying process.

The flow volume of an output valve provided at the tank can be regulatedby the controlling and evaluating unit by evaluating the determinedcomponents and concentrations of the pumpable organic waste. In additionto the determined components and concentrations of substances containedin the sample, previously determined soil values and the instantaneousspeed of the vehicle can also be taken into account by the controllingand evaluating unit to generate a suitable control signal for regulatingthe flow through an outlet valve while dispensing pumpable organicwaste. In this way, fertilization can be carried out corresponding tothe requirements of the soil.

Since the particle size of organic waste varies sharply and in somecases can lead to clogging, a cutting mechanism and/or sieve are/isadvisably arranged in front of the pump 2. Particles which are too largecan be made smaller in this way without changing the composition of thesample.

Determining the components of liquid manure is particularly important,for example, with a view to a precise use as organic fertilizer. Inorder to adhere to the applicable guidelines, it is useful to documentthe output amount of organic waste with respect to the components andconcentrations of individual ingredients. In this way, it is easy toverify the amount of organic waste that has been dispensed.

In the method according to the invention for the spectroscopicdetermination of the components and concentrations of pumpable organicwaste, the sample contained in a sample vessel 1 is pumped by a pump 2through a measurement cell 3 which forms a unit with the spectroscopicmeasurement head 4. The measurement head 4 carries out a spectroscopicmeasurement of the sample flowing through the measurement cell 3 bytransmission and/or reflection and conveys the measurement results forfurther processing to a controlling and evaluating unit. Thiscontrolling and evaluating unit determines components and concentrationsof substances contained in the sample based on stored specificcalibrations. Temperature-dependent, flow-dependent and sample-dependentspecific calibrations are required for this purpose.

The measurement cell 3 is preferably constructed in such a way that thesample flows between two windows which are integrated opposite oneanother in the measurement cell perpendicular to the flow direction. Thepump 2 can be regulated for adjusting the flow rate of the samplerequired for the spectroscopic measurement. In this way, it can beensured that no sedimentation, foaming or clogging occurs as the samplepasses through the measurement cell 3. The optimal flow rate variesdepending on the type of sample as a function of solids content,particle size, particle structure, and thixotropy.

To prevent corruption of measurement values, the measurement cell 3 iscleaned after measuring a sample. For this purpose, an existing watervessel is connected to the measurement cell 3 by a multi-port valve 6 inorder to remove residues of the measured sample. However, it is alsopossible to provide an additional vessel with cleaning liquid which isconnected to the measurement cell 3 by the multi-port valve 6. Aftercleaning, the measurement cell 3 is rinsed with water. In some cases,drying of the measurement cell 3 is required after cleaning and rinsing.The drying is carried out by aeration in that air is pressed through themeasurement cell 3 by means of a valve 7.

To prevent the influence of temperature on the measurement results, thesamples can be temperature-controlled prior to the measurement processby means of a device. This should preferably be carried out in or infront of the measurement cell 3.

In an advantageous construction, the described method can be applied toa vehicle, particularly for dispensing pumpable organic waste. Based onthe determined components and concentrations of substances contained inthe sample, an additional signal is generated by the controlling andevaluating unit for regulating the flow through an outlet valve whiledispensing pumpable organic waste.

In a particularly advantageous solution, previously determined soilvalues and the instantaneous speed of the vehicle are taken into accountby the controlling and evaluating unit in addition to the determinedcomponents and concentrations of substances contained in the sample inorder to generate a control signal for regulating the flow through anoutlet valve when dispensing pumpable organic waste.

In this way, liquid manure can be dispensed as organic fertilizer in aneven more purposeful manner. Purposeful metering is made possible bymeans of the previously determined soil values particularly whiledispensing.

The special advantage of the proposed technical solution consists inthat it is possible to carry out determinations of components andconcentrations of substances contained in the sample in a stationarymanner (at-line from sample vessels) or in a mobile manner (in-linewhile dispensing organic waste).

Further, spectroscopic measurement according to the principle oftransflection is particularly advantageous. In this way, it is possibleto carry out a direct measurement of the sample through light absorptionand/or light transmission without having to change the measurementconstruction. Depending on the sample to be measured, specifically thesolid, liquid and/or suspended organic waste contained therein, themeasurement delivers transmission and/or reflection measurement results.

The process of cleaning, rinsing and drying the measurement cell inorder to prepare it for the measurement of other samples can beautomated and regulated and monitored by the controlling and evaluatingunit. The process of cleaning, rinsing and drying can be monitored byspectroscopy. With reference to existing reference standards, the degreeof contamination and the relative humidity of the measurement cell canbe determined by the measurement head in connection with the controllingand evaluating unit.

When the “cell dry” state is detected, referencing is carried outthrough automatic white/black calibration of the spectrometer by meansof conventional known reference standards. Referencing of this kind canbe carried out periodically or as needed. The degree of contamination ofthe measurement cell can also be monitored by the system itself.

The solution according to the invention also offers the possibility ofself-calibration. After the process of cleaning, rinsing and drying hasbeen regulated and monitored by the controlling and evaluating unit, oneor more test liquids of defined composition and known absorption ortransmission can also be introduced into the measurement cell by meansof the multi-port valve. The spectroscopic signal can be calibrated andadjusted on the basis of this calibration liquid. A consistently highmeasurement accuracy of the system can be achieved in this way. Also,the test liquids used in this case can be expelled via the multi-portvalve 6 after the measurement cell 3 is rinsed out.

Complete partial samples or complete batches can be measuredcontinuously with the solution according to the invention withoutrequiring preprocessing of the samples. The samples are not changed bythe measurement process. The solution can be calibrated to a largenumber of relevant parameters and delivers a fast analysis with highmeasurement data density. Due to the very compact and robustconstruction, the solution is particularly suited to mobile use.

The solution is suitable for both in-line and at-line determination ofthe components of solid, liquid and/or suspended organic waste due tothe fast and continuous detection of measurement values.

While the foregoing description and drawings represent the presentinvention, it will be obvious to those skilled in the art that variouschanges may be made therein without departing from the true spirit andscope of the present invention.

What is claimed is:
 1. An arrangement for spectroscopic determination ofcomponents and concentrations of any pumpable material, comprising: asample vessel; a pump; and a measurement cell with a spectroscopicmeasurement head which carries out a nondestructive spectroscopicmeasurement of a sample of the pumpable material by light absorptionand/or light transmission; wherein said measurement cell is connected tothe pump, which can vary the flow rate, and to the sample vessel by apipe; wherein said spectroscopic measurement head and the regulatablepump have has electrical connections to a controlling and evaluatingunit; wherein the through-flow volume of an outlet valve provided in theoutlet line of the vessel is regulated by the controlling and evaluatingunit; and wherein the controlling and evaluating unit determinescomponents and concentrations of substances contained in the sample, andregulates the through-flow of the outlet valve based on the determinedcomponents and concentrations of the substances contained in the sample.2. The arrangement according to claim 1; wherein the measurement cell isconstructed in such a way that the sample flows between two oppositelylocated windows which are integrated in the measurement cellperpendicular to the direction of flow.
 3. The arrangement according toclaim 1; wherein a multi-port valve is arranged in the pipe to produceconnections to a water vessel and/or cleaning liquid vessel.
 4. Thearrangement according to claim 1; wherein the multi-port valve arrangedin the pipe can produce connections to one or more vessels with testliquids for self-calibration.
 5. The arrangement according to claim 1;wherein the multi-port valve has an actuating drive which is connectedto the controlling and evaluating unit.
 6. The arrangement according toclaim 1; wherein a device is provided for drying the measurement celland is connected to the controlling and evaluating unit.
 7. Thearrangement according to claim 1; wherein a device is provided forregulating the temperature of the sample and is connected to thecontrolling and evaluating unit.
 8. The arrangement according to atclaim 1; wherein the arrangement is connected to the outlet line of avessel arranged on a vehicle by two three-way directional valves.
 9. Amethod for the spectroscopic determination of the components andconcentrations of any pumpable material, comprising the steps of:pumping a sample contained in a sample vessel by a pump through ameasurement cell with a spectroscopic measurement head; allowing themeasurement head to carry out a nondestructive spectroscopic measurementof the sample flowing through the measurement cell by light absorptionand/or light transmission using the principle of transflectiontransmission and/or reflection; and conveying the measurement resultsfor further processing to a controlling and evaluating unit whichdetermines components and concentrations of substances contained in thesample based on stored specific calibrations.
 10. The method accordingto claim 9; wherein the pump is regulated to ensure the flow rate of thesample required for the spectroscopic measurement.
 11. The methodaccording to claim 9; wherein an existing water vessel is connected tothe measurement cell by a multi-port valve in order to remove residuesof the measured sample from the measurement cell and prepare themeasurement cell for the next sample.
 12. The method according to claim9; wherein an existing water vessel and a vessel with cleaning liquidare connected successively to the measurement cell by a multi-port valvein order to clean out residues of the measured sample from themeasurement cell, rinse the measurement cell, and prepare themeasurement cell for the next sample.
 13. The method according to claim9; wherein residual moisture is removed from the measurement cell by adevice for drying after the measurement cell has been cleaned.
 14. Themethod according to claim 9; wherein one or more vessels with testliquids for self-calibration of the arrangement is connected to themeasurement cell by a multi-port valve.
 15. The method according toclaim 9; wherein the sample is temperature-controlled by a device toprevent the influence of temperature on the measurement results.
 16. Themethod according to claim 9; wherein the measurement head carries out aspectroscopic measurement of the measurement cell without a sample inorder to determine the degree of contamination of the measurement cell.17. The method according to claim 9; wherein the cleaning and/or dryingof the measurement cell and a possible temperature regulation of thesample are/is controlled by the controlling and evaluating unit.
 18. Amethod comprising the steps of: pumping a sample to be measured by apump through a measurement cell which forms a unit with a spectroscopicmeasurement head; allowing the measurement head to carry out aspectroscopic measurement of the sample flowing through the measurementcell by transmission and/or reflection; and conveying the measurementresults for further processing to a controlling and evaluating unitwhich determines components and concentrations of substances containedin the sample based on stored specific calibrations; wherein said sampleto be measured is taken from the of an outlet line of a vessel ismeasured in-line; and wherein a control signal is generated by thecontrolling and evaluating unit based on the determined components andconcentrations of substances contained in the sample, and is used toregulate the flow through an outlet valve of the outlet line of thevessel.
 19. The method according to claim 18; wherein said sample to bemeasured is taken from the outlet line of the vessel, and wherein thesample is conveyed back into the outlet line of the vessel after beingmeasured.
 20. The method according to claim 18; wherein previouslydetermined soil values are taken into account by the controlling andevaluating unit in addition to the determined components andconcentrations of substances contained in the sample in order togenerate a control signal for regulating the flow through an outletvalve while dispensing pumpable organic waste.
 21. The arrangementaccording to claim 1; wherein the arrangement is mounted in its entiretyon a vehicle for dispensing pumpable organic waste.
 22. The arrangementaccording to claim 1, further comprising: means for conveying the sampleback into the outlet line downstream of the measurement cell.
 23. Themethod according to claim 19; wherein the vessel is arranged on avehicle.